1. Field of the Invention
The present invention relates to magnetic heads used in a magnetic disk apparatus for storing and reproducing data, and in particular, the present invention relates to a method for fabricating thin-film magnetic heads by the use of a thin-film forming technique.
2. Description of the Related Art
Thin-film magnetic heads have been increasingly used, in place of conventional monolithic magnetic heads, as magnetic heads in magnetic disk apparatuses for recording and reproducing data. With the recent development of magnetic heads having a small size and a large capacity, attempts have been made to minimize the distance between the magnetic head and the recording medium (the flying height) to realize a very dense recording format.
In a magnetic disk apparatus using magnetic disks having a relatively small diameter and thus a relatively low peripheral speed, proposals have been made in which magnetic head does not levitate above the recording medium but normally contacts the recording medium and has a sliding engagement therewith. In this case, the thin-film magnetic head is fabricated such that the supporting base structure of the magnetic head with the slider or the contact pad thereof is very light in weight and is biased with a relatively small elastic force so that the contact pressure of the magnetic head with the magnetic recording medium is small.
U.S. Pat. No. 5,041,932, for example, discloses such a small thin-film magnetic head. In this prior art, a plurality of thin-film magnetic heads are fabricated on a planar substrate such as a silicon wafer. Each of the magnetic heads has a base structure, a coil and a pole magnetically coupled with the coil to read data from and write data to the magnetic recording medium. The base structure has a pair (top and bottom) of surfaces, and a side surface perpendicular to the top and bottom surfaces. A spring arm is formed on the top surface of the base structure for mounting the magnetic head to an actuator of the magnetic disk apparatus and a contact pad for the sliding engagement with the magnetic recording medium is formed on the bottom surface of the base structure, with the spring arm and the contact pad formed unitary with the base structure. A coil is formed around a core which extends parallel to the spring arm and the coil and the core are formed within the base structure. A pole is formed on the side surface of the base structure and connected to the core. A return yoke is also arranged in the base structure near the bottom surface thereof to receive a magnetic flux emitting from the pole.
In the fabrication of the thin-film magnetic heads, the substrate is severed into a plurality of linearly elongated blocks after the coils of the magnetic heads are formed in the substrate, and the poles are subsequently formed on each of the elongated blocks. A problem is that the efficiency of the process is low since the poles must be formed, on each of the small elongated blocks, by a thin-film forming technique such as sputtering and photolithography and thus it is necessary to apply photo resist and position a mask on the small block. Also, many small blocks must be treated one by one and cannot be easily handled, so such a fabrication method is not suitable for mass production of the magnetic heads.
Other types of thin-film magnetic heads are known in which a plurality of thin-film magnetic heads are fabricated on a planar substrate such as a silicon wafer. Similar to the above described magnetic head, each of the magnetic heads has a base structure, a coil and a pole magnetically coupled with the coil to read and write data on the magnetic recording medium. The base structure has a pair (top and bottom) of surfaces, and a side surface perpendicular to the top and bottom surfaces. A spring arm is formed on the top surface of the base structure for mounting the magnetic head to an actuator of the magnetic disk apparatus and a contact pad for the sliding engagement with the magnetic recording medium is formed on the bottom surface of the base structure. In this case, however, the coil and the pole are formed on the side surface of the base structure.
In the contact type magnetic heads, it is desired that the pole which normally contacts the magnetic recording medium is wear-resistant. The contact pad surround the distal end of the pole, and the wear of the pole is mitigated if the wear of the contact pad is small. Accordingly, it is preferable to make the contact pad from a material harder than a material of the base structure of the magnetic head.
Also, it is preferable to fabricate the spring arm for mounting the magnetic head to an actuator of the magnetic disk apparatus separately from the base structure of the magnetic head to minimize the size of the magnetic heads on the substrate so that it is possible to increase the number of the magnetic heads obtainable from one substrate. The separate spring arm can be subsequently attached to the magnetic head.